rhel-8: use newer libgit2 sysdep

.woodpecker/update-package-index-redhat-8-arm64.yaml

@@ -33,6 +33,7 @@ steps:
     commands:
       - git clone https://pat-s:$$GIT_RO_TOKEN@git.devxy.io/devxy/build-binaries.git .
       - rm -rf /mnt/cache/packages/*
+      - rm -rf /mnt/cache/R-pkgs/gert /mnt/cache/R-pkgs/git2r /mnt/cache/R-pkgs/pkgbuild /mnt/cache/R-pkgs/processx /mnt/cache/R-pkgs/curl
       - R -q -e 'pak::pak("git::https://gitlab.com/devxy/r-package-binaries/bincraftr.git")'
       - R -q -e 'pak::pak("pat-s/cranlike@s3")'
       - R -q -e 'packageVersion("bincraftR")'